Hazardous chemicals for fireworks pyrotechnics and their raw materials

II. Categories of hazardous chemicals belonging to pyrotechnics and their raw materials
1. The concept of hazardous chemicals
Chemicals that are flammable, explosive, poisonous, corrosive, radioactive and other hazardous properties, and that are likely to cause injury or damage to personnel, equipment and the environment in the process of production, storage, use and disposal of waste are classified as hazardous chemicals.
Pyrotechnics and most of the raw materials used in the production of pyrotechnics, in the heat, friction, vibration, impact, contact with fire, moisture in water or with the performance of conflicting substances mixed together under the action of external factors, will cause combustion, explosion, corrosion, burns and poisoning and other catastrophic accidents, so most of them belong to the hazardous chemicals.
2. Classification of hazardous chemicals
As a result of the many varieties of hazardous chemicals, the nature of different, dangerous size, and a hazardous chemical often has a variety of hazards. If you do not grasp the multiple hazards of hazardous chemicals, it is easy to lose sight of the production, storage, transport, use and waste disposal of fireworks and fireworks accidents. However, each hazardous chemical, in its existence of a variety of hazardous properties, there is a major hazard that is the most prominent. Therefore, the national standard "Classification and Marking of Commonly Used Hazardous Chemicals" and "Classification and Numbering of Dangerous Goods" classify hazardous chemicals in accordance with the principle of "selective categorisation", and according to the main hazards of the chemicals, they are divided into 8 categories and 21 items.
(1) Explosives: they are divided into five categories, namely, substances and articles with overall explosion hazard, substances and articles with projection hazard but without overall explosion hazard, substances and articles with combustion hazard and lesser explosion or lesser projection hazard or both but without overall explosion hazard, explosive substances and articles without significant hazard, and very insensitive explosive substances.
(2) compressed and liquefied gases: divided into combustible gases, non-flammable gases and toxic gases and other 3 items.
(3) Flammable liquids: divided into 3 items such as low flash point liquids, medium flash point liquids and high flash point liquids.
(4) Flammable solids, self-combustible articles and flammable articles in contact with moisture: divided into 3 items such as flammable solids, self-smoking gunpowder manufacturing operations

flammable articles and flammable articles in contact with moisture and so on.
(5) Oxidisers and organic peroxides: divided into oxidisers and organic peroxides.
2 items.This article comes from: https://fireworkslit.com/Fireworkslit-https://fireworkslit.com/hazardous-chemicals-for-fireworks-pyrotechnics-and-their-raw-materials/

(6) Drugs.
(7) Radioactive substances.
(8) Corrosive goods: divided into acid corrosive goods, alkaline corrosive goods and other corrosive goods, etc.
3 items.
In these eight categories of hazardous chemicals, fireworks related to the main explosives, flammable liquids, flammable solids, spontaneous combustion of goods, flammable goods in the presence of moisture, oxidants and drugs.
3. The dangerous nature of pyrotechnics and their raw materials
(1) explosives. Refers to the external action (heat, pressure, impact, friction) can occur in a violent chemical reaction, the instantaneous release of a large amount of gas and heat, so that the surrounding pressure rises sharply, the explosion, causing damage to the surrounding environment of the goods; also includes a burning, projectile and smaller explosive hazards, or only produce heat, light, sound or smoke and so on, one or several effects of pyrotechnic articles. A substance is an explosive as long as it meets one of the following conditions:
① thermal susceptibility test burst point below 350 ℃;
② impact susceptibility test explosion rate of 2% or more;
③ burst speed of 3000 m / s above the material. Used to manufacture fireworks pyrotechnics and fireworks products, are explosives.
(2) flammable liquid. Refers to the normal temperature is very easy to catch fire and burn the liquid, liquid mixtures or liquids containing solid substances. The national standard stipulates that any liquid with a flash point equal to or lower than 61℃ is a flammable liquid. The flash point of flammable liquids is low, the boiling point is low, volatility is strong, the vapour mixed with air can form explosive mixtures, and has different degrees of toxicity. The flammable liquids used in the production process of fireworks are mainly solvents for resin-based binders, such as alcohol, banana water, toluene, petrol, etc.
() Flammable solids. Refers to solids with a low ignition point, sensitive to heat, impact and friction, easily ignited by external flames, burning rapidly, and likely to emit toxic fumes or poisonous gases, but does not include substances that have been listed as explosives.
(4) Self-igniting items. Do not need to be in contact with open flames, by their own chemical changes or by the environment
temperature, humidity, so that its exothermic, warming to reach the spontaneous combustion point and self-burning substances. Most of the self-igniting materials are easy to oxidise and decompose, and have a low ignition point. Before the fire, generally after a slow oxidation process, while generating a certain amount of heat. When the heat generated by the aggregation of the temperature reaches the material spontaneous combustion point, it will be spontaneous fire combustion. The presence of air, heat, moisture, oxidising agents, strong acids and metal powders can all promote spontaneous combustion. The charcoal powder in the raw material of black powder belongs to the spontaneous combustion items.
(5) Flammable articles in contact with moisture. It refers to the articles that undergo a violent chemical reaction and release a large amount of flammable gas and heat when they are exposed to water or moisture. Some of them can burn or explode without open flame. Commonly used in the production of fireworks in the wet flammable materials are aluminium powder, aluminium-magnesium alloy powder, zinc powder (Zn), silicon and aluminium alloy powder (Si + A1), ferrosilicon (FeSi) and so on.
When these flammable materials are exposed to water or moisture, a chemical reaction occurs with water to generate flammable gas hydrogen, and a large amount of reaction heat is released. The hydrogen released can form an explosive gas mixture with air and explode in contact with an ignition source.
(6) oxidising agent. Refers to the high oxidation state, with strong oxidising properties, easy to decompose and release oxygen and heat of the material, including inorganic substances containing peroxide, which itself is not necessarily flammable, but can lead to combustion of combustibles, and loose powder combustibles can be formed into explosive mixtures, heat, vibration or friction is more sensitive.
The oxidising agents used in pyrotechnics are mainly nitrates, perchlorates, peroxides, oxides, permanganates and non-oxygenated substances such as carbon tetrachloride and hexachloroethane.
Oxidisers are a class of substances with relatively active chemical properties, and they are a class of hazardous chemicals that are prone to accidents in the composition of pyrotechnics. The dangerous properties of oxidising agents are mainly as follows:
(1) Oxidisers are unstable and will decompose when they are heated, even causing combustion and explosion. For example, when potassium nitrate is heated over 350 ℃, it starts to decompose and release oxygen.
② The explosiveness of many oxidising agents is also prominent, especially some chlorates and nitrates. When mixed with combustible impurities, this explosive is more obvious, by friction, vibration, heat, can cause an explosion.
(iii) oxidising agent meets organic matter, flammable goods, combustible goods, etc. will be a violent reaction, and even cause combustion and explosion. and some of the original non-explosive chemicals mixed together, immediately after a violent chemical reaction, sometimes even without any external factors
can spontaneously explode without any external factors to stimulate.
④ some oxidants will decompose in contact with water, especially peroxide of active metals (such as Na2O2) in contact with water to release flammable gases. Therefore, these oxidants should be protected from moisture or rain, and water is strictly prohibited to extinguish fire.
⑤ Most of the oxidising agents can undergo chemical reactions when they meet acids, and the reactions are often violent and even cause explosions.
(6) Some oxidising agents will decompose quickly and release oxygen under sunlight irradiation, so oxidising agents should be avoided from gaze irradiation, and the glass of the storehouse should be painted white.
(vii) Most oxidants will absorb water vapour in the air and react when they are not packed tightly. So the oxidising agent should be kept well packed, and if it is broken, it should be dealt with in time.
(8) Many oxidants also have a certain degree of toxicity and corrosiveness, so contact with oxidants should pay attention to safety protection.
(7) there are drugs. Refers to enter the body, the accumulation of up to a certain amount, and body fluids or organs and tissues can occur with biochemical effects or biophysical changes, disturbing or destroying the normal physiological function of the body, causing temporary or persistent pathological state, or even life-threatening items.
Hazardous chemicals in this category mainly refer to substances that are susceptible to poisoning when introduced into the human body in small quantities. It must be noted that the meaning of having drugs is relative, any chemical, including most of the chemical raw materials used to manufacture pyrotechnics, as long as there are certain conditions, are likely to show toxicity. In the case of fireworks manufacturers, the possible routes of entry of poisons into the human body include the respiratory tract, the digestive tract and the skin.
① The respiratory tract is the most important way for poisons to enter the body. In the production process of fireworks, a variety of toxic chemicals will exist in the form of dust in the operating environment of the air, can be with the operator's breathing, through the respiratory tract into the body. Human lungs are composed of billions of alveoli, alveolar wall is very thin, the wall is rich in capillaries. Once the poison enters the lungs, it will soon enter the blood circulation through the alveolar wall and be transported to the whole body. The higher the concentration of toxic substances in the air of the operating environment, the easier it is to cause poisoning. Therefore, the operator must wear a good anti-virus mask in the production of toxic dust generated by the place of work.
② poison absorbed through the skin caused by poisoning is also relatively common. Production process with direct contact with toxic chemical materials, or flying dust attached to the body, it is possible to make the toxic substances absorbed through the skin caused by the human body poisoning. Therefore, in contact with toxic chemical materials
Therefore, in contact with toxic chemical materials, operators should wear working clothes and protective gloves, and should shower and change clothes at the end of work. Poor personal hygiene habits may cause poisoning by absorption of toxic substances through the digestive tract. Poisons absorbed through the digestive tract are mostly due to poor personal hygiene habits, hand-contaminated poisons enter the digestive tract with food or water. Into the respiratory tract after the removal of insoluble poisons, can also be swallowed through the pharynx and enter the digestive tract. Therefore, operators of fireworks factories should develop good hygiene habits and wash their hands before eating or drinking.This article comes from: https://fireworkslit.com/Fireworkslit-https://fireworkslit.com/hazardous-chemicals-for-fireworks-pyrotechnics-and-their-raw-materials/ This article comes from: https://fireworkslit.com/Fireworkslit-https://fireworkslit.com/hazardous-chemicals-for-fireworks-pyrotechnics-and-their-raw-materials/